Lifting-jack.



4'Il o. sT. PIERRE.

LIFTING JACK.

APPLICATION PILEDMARA, 1912.

Patented Mar. 9, 1915.

2 SHEETS-SHEET 1.

JW" WIP,

J. o. ST. PIERRE. LIFTING JACK.

APPLICATION FILED MARA, 1912.

' www@ Patented Mar. 9, 1915.

weer A a n Snecnicaton ci Leiters Paienu.

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reiirnee ce iiing jacks nnfi y that cinss of ichs `which are 're/n es rnche'u screw jacks, anni has for its ehieci. to produce :i self lowering sci; which wil? run down qnickiy under its iced,

invention consists in" providing the jack with an extended 'trein of reduction gearing, the inw speed end of which is nfiepteci he he driven by the main operaring gear sjpiiniie of 'ehe jack only as the latter mores in e reverse direction so its nioveinenr in iifing; the jncir, and ehe high speed. end o;- -,he rein of gearing being edepteci to drive fricgion member with which. n hand conn'oiieci ,reife coperzltes. lThe trein ci reciucion gearing is sniicienziy exended eo inni; its inercia Wiii snhstentieiiy reterci speed of descent he jack under its ion- Y o and. 'Wiii ineke ii; possible Afor n iigh; enfl ifreeiy operable ricion 1crniie to bring' fk-he jeci-z instantly to resiJ when descending nncier nie.v in'nnn londe. uoiiize ii'etche'; ineens for enoinaticeiiy disconnecting the train of reciueion gearing from he gein* when 'he atter is nurned. no raise finch u mier its ionfi.

l iii. i f ieion urher consists in certain `s 5rncion cfc n., nce to ehe description ci i. 'io lhe cieirnehercinefer wings: Figure represents e tion oli e embody'- cf 'his inreni n, che cureriicei eecgion of the sanne7 Jiane being on iinc 2.-2 on rep'rsser enlarged. vertlcei i. ming mechanism for con .l une; and lowering oi 'the nioveher he 'hinein he cuibiiing piene on iine'w on Fig. 2 if e repre r eecion looking in 'che oline 1e cu 'ieg piane being on line i rig. 5 represents en eiein section ef one. emhesiiineni;

the deif'iee for controiiing or arresting the movement of seid operating; niechenisni.

characters designate like pers 'ihe several figures of the draw i 1 e stationery standard 'il fver he periphery of which is 'eii (L movable sleeve l2, 'to the upper enci of which is hreedeci e cap 13. in the upper which is thi-ended e lifting screw 1.5 having spi'ined to upper reduced end e geni: 1G with .which meshes a gear 17 formed upon or secured to e revoiubie shaft or spindie l, Ahe einer end of which is provided with e suitable operaing mechanism 19 of any weil known construction, Interposed between he' upper fece of lthe gen1' 16 and the inner ince of the can 13 are two annular plates 20 and Q1, between which are interposed, a piu.- reiity of enifriction members 22.

Secured to the gear 17 by means oi the screws 19 is n mcher 2OK with the teeth of which engage n plurality of spring pressed end of che sandard l1 is mounted enut 14- to ifrcefy revoinhie and mounted upon e re cinccf portion 23 of ehe cylindrical huh 21;- iierni'ing e, hearing for seid Spindle or shaft This huh Q/eis formed integr-n1 wich e reinovnhie plate '25 secured to the flanged progectien 26 forming :L part of the movabie member 1Q. The gear Q2 meshes with n pinion secured to or formed integral with n rcvoiubie member 27 to which is :riso secured :i S28 meshing with a pinion 29 formed 'upon or .secured f to a. re'voiubie meniher 3C eo which is also secured n geur 3l meshing wih the pinion 32 formed upon or secured to e revoluhie member 33 te which is aise securefi e gear Bei, which in meshes Wzh'e pinion 35 formed upon or secured to e'revoiuhie member 3G. Secured to and revoiubiewith zhe rncinher 36 n disk S7 extending through e slot 3S in i'he wcii o'f' bhe hoxlihe Hnge 26. The fieng'c '26 has formed thereon en ear 39 and che removnhie piene 25 has similar enr 39 formed `ehercon. Euch of the eers 39 and 39 hns monn'ceci therein n cyiinciricei member Gili having a friction pad, i2 secured to one end and a head 43 formed upon the oher end. between which and the eers 39 or 39*K is e spline; 44- edepte to nornieiiy retain, sai pad. fi-E rree from ccnact with the sifie face of ehe dish interpose'i be'ween seid pride.

Each ofthe ears 39 an 39* has pivotally secured thereto at 45 a lever 46 one end of which bears upon the outer end of the headed member 4l1 While the other end thereof has'pivotally secured at 47 a nut 48, said nuts 48 beiny in alinement. Threaded to said nuts..48 1s a threaded member 4.9.having formed thereon intermediate said nuts 48ineans such as the enlarged milled portion 50 turning said threaded member 49 about its axis.

In the operation of the device -When bit is desired to raise the movable member 12 the operating mechanism 19 is manipulated, to turn the spindle 18 and gear 17 formed thereon in a direction opposite to that indicated by the-arrow a on Fig. 4 'of the drawings. When this is done the ratchet 20 will freely pass the pawls 21 without disturbing the train of gearing actuated by the driving gear 22, to Whichth'e pawls 21 are pivotally secured. During this operation the `friction' pad 42 may be 1n contact with the face of the disk 37 or not as, desired. n A

Then the weight is lifted itit is desired to retain it in its lifted position the threaded member -49 maybe operated by the milled portion 504 to move the levers 46 about the pivots 45 so. that the pads 42 will be brought into frictional contact with the face of the disk 37 to prevent anymovement of the gears. The loadA on thecap 13 would tend to move the gears 17 and spindle 18 in a direction opposite to that indicated by the arrow a on Fig. 4. This reverse movement would cause the pawls 21 to engage with the teeth of the ratchet 20 and as soon as the train of gearing has been locked from rotation by means of the friction pads 42, such reverse movement would be etlectually prevented.

Whenever it is 4desired to lower the movablemember 12 the friction pads 42 may he removed from the disk and with the pawls 21 in engagement with the teeth of the ratchet 20 the train of gearing will be driven by the rotation of the gear 17 and its spindle 18. This train of gearing is geared up to such'an extent that its inertia substantially retards the lowering o the jack and at the same time it produces a very high rate of 'speed for the revoluble member 3G and the disk 37. -Should an excessive load be upon the cap 13 so that the member 12 moves vdownwardly too rapidly, the movement may be arrested by simply seizing the disk 37by the hand or by forcing into con- ,tact with the side faces thereof the friction pad 42, the high rate of speed at which the disk is driven acting to multiply the frictional power applied thereto so that a light pressure-of' a hand or friction brake will serve to instantly stop the descent of the jack, thereby making'it 'possible for the jack to be lowered very` rapidly and yet to not only to hold the load on the jack but to' control its descent. The result of such an arrangement would be thatl the jack would descend in jerks, starting rapidly and requiring the application of strong brake power to arrest it. It is to avoid the dangers incident to such operation of the jack that I have interposed the high ratio reduction gearing which has suflicient inertia itself to largely resist any excessive-speed of descent on the-part of the jack under its load, and which at the same time greatly multiples a light braking power `so that the latter will stop the jack easily and without causing jerks or jars. When these pads 42 are in Contact` with the face of the disk 37 the rotation of the spindle A18 will be controlled through the train of gearing or may 'iighenan extreme weight is supported by the jack the tendency would be for'the screw 15 to move downwardly in its nut 14 unless some provision was provided to efi'ectuzilly prevent such movement. It is self-evident that while, by the mechanism described,

such accidental lowering of the jack is wholly obviated, whenever it becomes necessary to lower the jack quickly by means of the operating mechanism such operation is possible.

It is believed that the operation and many advantages of the invention will be thoroughly understood from the foregoing.

Having thusdescribed my invention, I claim:

1. In a quick action self lowering jack, the combination, of a stationary member, a

movable member, a revoluble member for raising and lowering said movable member, a shaft, a gearing having a low ratio of'speed reduction transmitting motion fromv said shaft to the revoluble member, an extended train of gears having a high ratio of speed multiplication and adapted to act as a speed controller and retarder, a pawl and ratchetdrive between said shaft and the 'low speed end of said multij'ilying gearing,

gears designed andfadapted to produce a.`

high ratio of" speed multiplication` and to be arrested completely, It is obvious thatA in. La

manana act as a .speed controller andretarder', a gear casing in which said gears: are mount ed, a pawland ratchet drive between said shaft and multiplying gearing* to disconnect the latter from the shaft when the latter is turned to raise the jack, a friction disk driven by the. high speed end of said multiplying gearing and exposed to-be controlled by hand, and brake means ladjustable to positively engage said friction disk, sirbstantially as described.

3. In a quick action self lowering jack, the combination of a stationary member, a movable member, a revoluble member` for raising and lowering said movable member, a shaft, a driving connection between said shaft and revoluble member, an extended train of gears, a pawl and ratchet driving connection between the I low speed end of said train of gears and parts movable with said movable member and adapted to drive said trainof gears only during the descent of said revoluble member, said gears having a sufliciently high natio of speed multiplication-to substantially retard by its inertia the sped of descent of said movable member, a friction brake element driven by the high speed end of said'train of' gears, and a freely and manually adjustable brake which co-acts with said.A friction element, substantially as described.

Signed by me at 4 lljost Oilice Sq., 130sn ton, Mass., this 26th day .of February, 1912.

JOSEPH 0. ST. PIERRE;

Witnesses:

WALTER E. LOMBARD, NATHAN C. LOMBARD. 

